Rotary anode for X-ray tube and method for manufacturing the same

Abstract

A rotary anode for use in an X-ray tube has a graphite substrate plate, an intermediate layer made of a metal that does not react with graphite, and an X-ray generating layer provided on the intermediate layer for generating X-rays when electron impact is applied. The intermediate layer is a rhenium film having an equiaxed grain structure. A method for manufacturing such a rotary anode is proposed. The method has the step of forming, on a graphite substrate plate, an intermediate layer of rhenium by subjecting a metallic chloride to the thermal decomposition CVD process at a substrate temperature of 1200° C. or more. The method further has the step of forming, on the intermediate layer, an X-ray generating layer of tungsten or tungsten-rhenium alloy by subjecting a metallic fluoride to the hydrogen reduction thermal CVD process.

What is claimed is: 
     
       1. A rotary anode for use in an X-ray tube comprising a graphite substrate plate, an intermediate layer made of a metal that does not react with graphite, and an X-ray generating layer provided on said intermediate layer for generating X-rays when electron impact is applied thereto, characterized in that said intermediate layer is a rhenium film having an equiaxed grain structure and being free from a columnar grain structure, said rhenium film having an average grain size of about 10-50 microns, and wherein the thickness of the intermediate layer is in the range of about 10 to 50 microns. 
     
     
       2. A rotary anode for use in an X-ray tube comprising a graphite substrate plate, an intermediate layer which does not react with graphite and an X-ray generating layer provided on the intermediate layer for generating X-rays when electron impact is applied thereto, said intermediate layer having a thickness of about 10 to 50 microns and made of rhenium having an equiaxed grain structure which is free of a columnar grain structure, and having an average grain size of about 10 to 50 microns, said rotator anode being produced by forming, on a graphite substrate plate, an intermediate layer of rhenium by subjecting a metallic chloride to a thermal decomposition CVD process at a substrate temperature of 1200° C. or more, and forming, on said intermediate layer, an X-ray generating layer of tungsten or a tungsten-rhenium alloy by subjecting a metallic fluoride to a hydrogen reduction thermal CVD process.